fix: 修复演练会签预览问题

src/views/emergency/emergency-drill/components/DrillImplementation.vue

@@ -57,7 +57,8 @@
   }>();
   const previewOnlineRef = ref<InstanceType<typeof PreviewOnline>>();
   const handlePreviewScript = (str: string) => {
-    const file = JSON.parse(str);
+    const obj = JSON.parse(str);
+    const file = Array.isArray(obj) ? obj[0] : obj;
     const url = file.fileUrl;
     const type = file.fileType as keyof typeof FILE_TYPE_ICON;
     if (!url) return;